Abstract

Introduction: This work describes a technique for characterizing the gradient subsystem of a Magnetic Resonance (MR) system. Methods: The technique uses a Fourier-transform analysis to directly measure the k-space trajectory produced by an arbitrary gradient waveform. In addition, the method can be easily extended to multiple dimensions, and can be adapted to measuring residual gradient effects such as eddy currents. Several examples of gradient waveform and eddy-current measurements are presented. Also, it is demonstrated how the eddy-current measurements can be parameterized with an impulse-response formalism for later use in system tuning. Results/Conclusions: When compared to a peak-fitting analysis, this technique provides a more direct extraction of the k-space measurements, which reduces the possibility of analysis error. This approach also has several advantages as compared to the conventional eddy-current measurement technique, including the ability to measure very short time constant effects.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Center for Research Resources (NCRR)
Type
Biotechnology Resource Grants (P41)
Project #
5P41RR009784-04
Application #
6282966
Study Section
Project Start
1998-01-01
Project End
1998-12-31
Budget Start
1997-10-01
Budget End
1998-09-30
Support Year
4
Fiscal Year
1998
Total Cost
Indirect Cost

  Institution

Name
Stanford University
Department
Type
DUNS #
800771545
City
Stanford
State
CA
Country
United States
Zip Code
94305

  Publications

Maclaren, Julian; Aksoy, Murat; Ooi, Melvyn B et al. (2018) Prospective motion correction using coil-mounted cameras: Cross-calibration considerations. Magn Reson Med 79:1911-1921
Guo, Jia; Holdsworth, Samantha J; Fan, Audrey P et al. (2018) Comparing accuracy and reproducibility of sequential and Hadamard-encoded multidelay pseudocontinuous arterial spin labeling for measuring cerebral blood flow and arterial transit time in healthy subjects: A simulation and in vivo study. J Magn Reson Imaging 47:1119-1132
Kogan, Feliks; Hargreaves, Brian A; Gold, Garry E (2017) Volumetric multislice gagCEST imaging of articular cartilage: Optimization and comparison with T1rho. Magn Reson Med 77:1134-1141
Aksoy, Murat; Maclaren, Julian; Bammer, Roland (2017) Prospective motion correction for 3D pseudo-continuous arterial spin labeling using an external optical tracking system. Magn Reson Imaging 39:44-52
Tamir, Jonathan I; Uecker, Martin; Chen, Weitian et al. (2017) T2 shuffling: Sharp, multicontrast, volumetric fast spin-echo imaging. Magn Reson Med 77:180-195
Lai, Lillian M; Cheng, Joseph Y; Alley, Marcus T et al. (2017) Feasibility of ferumoxytol-enhanced neonatal and young infant cardiac MRI without general anesthesia. J Magn Reson Imaging 45:1407-1418
Taviani, Valentina; Alley, Marcus T; Banerjee, Suchandrima et al. (2017) High-resolution diffusion-weighted imaging of the breast with multiband 2D radiofrequency pulses and a generalized parallel imaging reconstruction. Magn Reson Med 77:209-220
Uecker, Martin; Lustig, Michael (2017) Estimating absolute-phase maps using ESPIRiT and virtual conjugate coils. Magn Reson Med 77:1201-1207
Bian, W; Tranvinh, E; Tourdias, T et al. (2016) In Vivo 7T MR Quantitative Susceptibility Mapping Reveals Opposite Susceptibility Contrast between Cortical and White Matter Lesions in Multiple Sclerosis. AJNR Am J Neuroradiol 37:1808-1815
Vos, Sjoerd B; Aksoy, Murat; Han, Zhaoying et al. (2016) Trade-off between angular and spatial resolutions in in vivo fiber tractography. Neuroimage 129:117-132

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